Preparation of unsaturated alcohols and ethers

ABSTRACT

UNSATURATED ALCOHOLS AND ETHERS ARE PREPARED THROUGH THE REACTION OF C4 TO C6 ALIPHATIC CONJUGATED DIOLEFINS WITH WATER, A LOWER ALKANOL OR MIXTURES THEREOF IN THE PRESENCE OF A ZERO VALENT PALLADIUM BASED CATALYST SYSTEM. THE PREFERRED CATALYST IS TETRAKIS(TRIBENZYLPHOSPHINE) PALLADIUM TETRAKIS(DIPHENYLALKLPHOSPHINE)PALLADIUM OR TETRAKIS(TRIPHENYLPHOSPHINE)PALLADIUM ALONE OR IN COMBINATION WITH A BASIC MATERIAL SUCH AS A QUATERNARY AMMONIUM HYDROXIDE. WHERE ONE OF THE COREACTANTS IS WATER, THE REACTION IS CONDUCTED IN THE PRESENCE OF A SOLVENT. THE UNSATURATED ALCOHOL AND ETHER PRODUCTS CAN BE CATALYTICALLY HYDROGENATED TO PLASTICIZER ALCOHOLS AND ETHER SOLVENT MEDIA.

United States Patent 3,769,352 PREPARATION OF UNSATURATED ALCQHOLS ANDETHERS Michael G. Romanelli, New York, N.Y., assignor to Esso Researchand Engineering Company No Drawing. Continuafion-in part of applicationSer. No. 808,673, Mar. 19, 1969, now Patent No. 3,670,032. Thisapplication Feb. 8, 1971,- Ser. No. 113,591 The portion of the term ofthe patent subsequent to June 13, 1989, has beendisclaimed Int. Cl. C07c41/06, 41/10 U.S. c1. 260-614 AA} 8 Claims ABSTRACT OF THE DISCLOSUREBACKGROUND OF THE INVENTION (I) Field of the invention This is acontinuation-in-part application of U.S. Ser. No. 808,673, now U.S. Pat.No. 3,670,032.

This invention relates to a process for the formation of unsaturatedalcohols and ethers. More particularly, this invention relates to thepreparation of unsaturated aliphatic alcohols and ethers through theliquid phase reaction of aliphatic conjugated diolefins with Water,aliphatic alcohols or mixtures thereof in the presence of a zero valentpalladium based catalyst system.

(II) Description of the prior art ,Unsaturated aliphatic alcohols andethers are well known articles of commerce and have been preparedutilizing a variety of techniques. One previously proposed method forthe preparation of lower alkyl ethers involved the catalyzeddimerization of butadiene in the presence of a lower alkyl alcohol (seeTakahasi. Tetrahedron Letters, p. 2451 (1967) The catalysts suggestedfor use were tetrakis(triphenylphosphine) palladium andbis(triphenylphosphine) palladium maleic anhydride adduct. While thecatalyst system served to promote the reaction to the desired .etherproducts, the yields were relatively small based upon the amount ofpalaldium employed.

SUMMARY OF THE INVENTION Now, in a'ccordancejwith the present invention,it has been found thatboth unsaturated alcohols and unsaturated etherscan be'readily formed through the catalyzed di- 'merization ofconjugated aliphatic diolefins in the pres- ,ence of water, a loweralkyl alcohol, ormixtures thereof.

The reaction is conducted in the liquid phase; normally in the presenceof a reaction diluent. Most preferably, the reaction system ishomogeneous and the reaction is conducted at atemp'eratureless thanabout 160 C. in the f substantial absence' ofoxygenr-Thepreferredcatalysts are tetralcis (tribenzylphosphine) palladium,tetrakis;(diphenyl alkylphosphine)palladium ortetrakis(triphenylphosphine) palladium alone or'incombination' with abasic cocatalyst.

The manner in which the reactions proceed is demonstrated in thefollowing representative equations:

Equation I illustrates the reaction of two moles of butadiene with waterto form 1-octa-2,7-dienol. Equation II illustrates the reaction of twomoles of butadiene with a monoalcohol to form the correspondingoetadienyl ether. In addition to the major products, minor amounts ofbyproducts including butadiene dimers such as 1,3,7-octatriene are alsoformed. The starting olefin is preferably a C to C conjugated diolefinichydrocarbon. Examples of useful olefin materials include acyclicmaterials such as butadiene, isoprene and piperylene.

When an alcohol is employed as a coreactant, it is preferred that thealcohol be a lower acyclic or alicyclic monoalcohol having the generalformula ROH wherein R designates a monovalent straight chain, branchedchain or cyclic alkyl radical having from 1 to 8, preferably 1 to 5,carbon atoms. The reaction rate varies markedly with the type of alcoholcoreactant used. For example, reactions wherein a straight chainalkanol, e.g., ethanol or methanol, is used proceed in a rapid fashion;however, when the alcohol is a branched chain material, such as tertiarybutyl alcohol, the reaction proceeds relatively slowly. The palladiumbased catalyst employed is decomposed to metallic palladium whencontacted with oxygen. Hence, maximum catalyst eifieiency is securedwhen the diolefin, water and alcohol reagents are stripped prior to useto remove any dissolved oxygen. Oxygen removal can be achieved bysparging with nitrogen or other inert gas.

The instant reaction may be carried out in bulk; that is, in the absenceof a solvent or in the presence of an organic diluent that does notdecompose the zero valent palladium based catalyst. Reactions involvingan alkyl alcohol can be carried out in the absence of a diluent in thatthe olefinic material is readily soluble in the alcohol and the desiredhomogeneous system is secured. When water is employed as the processcoreactant or in situations wherein appreciable quantities of water arepresent within the reaction zone, a solvent system should be usedbecause the diolefin is substantially insoluble in water. Heterogeneousreaction systems should, in general, be avoided as the complex palladiumcatalyst is preferentially soluble in organic materials. Hence, areaction between a diolefin and water will not proceed at a commerciallyviable rate in the absence of a co-solvent for both the water and theolefin since the palladium catalyst will tend to collect in the diolefinlayer.

With the exception of nitrogen-containing materials such as amines,amides, nitriles, etc., any type of material that will solubilize thediolefin and the hydroxy conco-ntaining coreactant may beused as theprocess solvent. Alcohols and ethers,'especially lower alkyl alcoholsand ethers having from 1 to 5 carbon atoms, are the preferred reactionsolvents. Most preferably, branched chain alcohols, e'.g.,seco'ndary andtertiary alcohols, especially tertiary alcohols, are used because, whileparticipating inthe' reaction ,"they do so ata relatively slow rate.Useful solventslinc'lude isopropanol, t-butanol, tetrahydrofu'ran, etc.Y

The ratio of process reactants to solvent is not critical andmayvaryover a wide range. Ordinarily only a sufficient quantity'cfsolvent is; used to insure the desired singlef'phase' reaction system.Typically, in a reaction system wherein water is'used as a coreactant,the reaction syste'mfbefore addition of diolefin, will be composed offrom to fil);volumepercent, preferably 20 to 30 volume percent, of waterwith the balance of the system made up of solvent. In water'containingsystems, generally about 0.5 to 2.0 moles of butadiene are used perliter of solvent. Most preferably from 1.0 to 1.5 moles of diolefin areused per liter of solvent. In systems wherein water is not used as thecoreactant, the molar ratio of diolefin to alcohol within the reactionzone can vary between about 0.01:1 to 3:1, preferably 0.1:1 to 1:1.

The process is conducted in the presence of a catalyst system composedof a zero valent palladium material; that is, zero valent palladium or amaterial that will generate zero valent palladium at reactionconditions, a phosphine or isonitrile activator and, optionally, a basiccocatalyst material. Materials that will generate the desired zerovalent palladium at reaction conditions include materials such as hispi-allyl) -palladium,

tetrakis (trib enzylphosphine )palladium,tetrakisdiphenylalkylphosphine) palladium, tetrakisphenyldialkylphosphine) palladium, tetrakis (trialkylphosphine)palladium and tetrakis (triphenylphosphine) palladium.

The activator compounds that can be employed in conjunction with thesource of zero valent palladium are phosphine and isonitrile materials,preferably compositions having the general formulas:

R1R2R3P and wherein R R R and R are monovalent, substituted orunsubstituted organic radicals having from 1 to 20, preferably 1 to 14,carbon atoms per radical. Preferably, R R R and R are monovalent acyclicor alicyclic alkyl radicals having from 1 to 20, preferably 1 to 14 andmost preferably 1 to 12 carbon atoms, such as methyl, propyl, isobutyl,cyclohexyl, etc.; phenyl radicals; monovalent alkylaryl radicals havingfrom 7 to 12, preferably 7 to 10, carbon atoms, e.g., tolyl, xylyl,ethylphenyl, etc., and monovalent aralkyl radicals having from 7 to 12,preferably 7 to 10, carbon atoms, such as benzyl, ethylbenzyl,diethylbenzyl, etc.

Isonitrile compounds are conveniently prepared by heating a primaryamine with chloroform and sodium hydroxide. The phosphine activatormaterials are generally prepared by reacting a phosphorous halide, e.g.,phosphorous trichloride, with an alkyl or aryl organometallic compounds,such as butyl lithium, phenylmagnesium chloride, etc. Representativeexamples of useful activator compounds include triphenylphosphine,tricyclohexylphosphine, tributylphosphine, diethylphenylphosphine,methyldiphenylphosphine, tris(para-tolyl)phosphine,tris(metatolyl)phosphine, tris(4-methylcyclohexyl)phosphine,tris(xylyl)phosphine, triethylphosphine, tribenzylphosphine,tris(phenylethyl)phosphine, methylisonitrile, ethylisonitrile,t-butylisonitrile, cyclohexylisonitrile, phenylisonitrile,p-tolylisonitrile, etc.

The performance of the catalyst system can be greatly enhanced by usingeither an organic or inorganic base material in conjunction with thezero valent palladiumactivator system. Preferred basic materials includequaternary ammonium hydroxides having from 4 to 20, preferably 8 to 10,carbon atoms, quaternary ammonium alkoxides having from 4 to 20,preferably, 8 to 12, carbon atoms, alkali and alkaline earth metalhydroxides, and alkali and alkaline earth metal alkoxides having from 1to 10 carbon atoms. Since the use of inorganic hydroxides normallyadversely affects the solubility of the diolefin.

reagent withinthe reaction system, it is preferred that organic basematerials, especially quaternary ammonium hydroxides, and alkoxides,'be. used as the process, co-

catalysts. Useful cocatalyst materials. include tetraalkylammonium?hydroxides, tetraalkylam'monium alkoxides,"

ides, hydroxides, and alkoxides such as sodium, potassium and lithiummeth'oxide, ethoxide, isopropoxide, t-butoxide, etc.

The palladium catalyst is ordinarily employed in amounts ranging fromabout 0.0001 to 0.01 mole of catalyst per liter of alcohol and/ orsolvent present within the reaction zone. In most instances, thepalladium catalyst is insoluble at concentrations greater than about0.01 mole of catalyst per liter of solvent and/or alcohol. It ispreferred that about 0.001 mole of catalyst be used per liter of solventand/or alcohol present within the reaction zone.

The concentration of the activator within the reaction zone can varyover a wide range. When a phosphine material is used, it is preferredthat it be employed in molar excess relative to the zero valentpalladium material. Up to about moles of phosphine compound may be usedper mole of zero valent palladium compound. Preferably, at least about 1to 10 moles phosphine activator are used per mole of zero valentpalladium material. When an isonitrile activator is used, it ispreferred that at least about 1 mole of isonitrile compound be employedper mole of zero valent palladium material. Preferably, about 1 to 4moles of isonitrile activator compound are used per mole of zero valentpalladium compound. When large excesses of isonitrile compound are usedrelative to the zero valent palladium material, the reaction tends tostart rapidly but then stops after a relatively brief reaction period.The source of zero valent palladium and the activator compound may becombined in a single complex or molecule, such astetrakis(tribenzylphosphine)palladium ortetrakis(triphenylphosphine)palladium. In such situations, it is notessential that additional amount of activator be employed; however, itis ordinarily preferred to use greater than stoichiometric amounts ofactivator compound.

The basic cocatalyst may be used at concentrations substantiallyidentical to or higher than the palladium catalyst concentration. Atleast about 0.0001 mole of base is used per liter of alcohol or solvent.The upper limit on base concentration may vary over a wide range as itis possible to use more than about 0.1 mole of base per liter of solventor alcohol. However, the presence of a basic material adversely affectsthe solubility of the olefin in the reaction system. Hence, it isordinarily desirable to maintain the base concentration at the lowesteffective level consistent with a desirable reaction rate for the amountof olefin dissolved within the reaction system. 4

The reaction is conducted in the liquid phase at temperatures belowabout C. Although the reaction proceeds at a much faster rate atelevated temperatures, the palladium catalyst tends to be inactivated attempreatures much above about 160 C. Typically, the reaction is carriedout at a temperature ranging between about 0 and 160 C., preferablybetween 50 and 140 C. The reaction pressure, that is the pressuremaintained within the reaction zone, may vary over a wide range as bothatmospheric and superatmospheric pressures may be used. Typically, thepressure within the raction zone is the autogenous pressure exterted bythe'reactant's and solvent at the reaction temperature. The length ofthe reaction period depends upon a number of process variables. In mostinstances, high product yields are secured at the above describedtemperature and pressure conditions within about 0.1 to 60 hours. Moretypically, substantial product yields are secured within from 0.5 to 20hours at the above temperature and pressure conditions. H Theunsaturated alcohol and ether compounds produced according to theprocess of this invention have many varied uses. Principally,thecompositions may be hydrogenated in the liquid phase in the presenceof a typical hydrogenation catalyst such as nickel, platinum orpalladium and reduced to thecorre'sponding saturated alcohols andethers. The'alcohol product can be reacted 6 with phthalic anhydride toform .useful, polyvinylchloride reacted with water in the presence of anisopropanol diluplasticizermaterials'.Additionally, the saturatefalcoh'ols enti 'Iu'fjea cli case,tetrakis(triphenylphosphine) palladiumcanbe used as ingredients in cosmetic 'formulati f] us jed'as catalyst.Sodiumjhydroxidecocatalyst was saturated ethers may be employed forsolvent applica u'sediri'RunNol. Theconditions'at which'each of thetions, particularly as constituents in paint or ;varnish comexperimentswere carried out as well as the results of the positions. f -experimentsare set forth in Table I below.

. TABLEI n+1) mantra (CHahCHOH v A BY 011+ C ocmcnom 0 D I Yield of BWt. percent (PhaP)4 Pd, H20, (CH3)1CHOH, Temp., Time, Product, G./g.G.lg. Run No g. g. ml. ml. 0. hrs g. A B C D catalyst Pd 1 Initialcharge-not all consumed;

b 2.0 ml. 50% NaOH added. 6 Temperature not maintained during entireperiod. 7

DESCRIPTION OF- THE"'PREFERRED The above data'clearly'indicate theeffectiveness of the EMBODIMENTS 25 palladium catalyst and base inpromoting the formation w of both unsaturated ethers and alcohols. Asshown in t g: gfi ggg g g z glide-[stood by-refe-renc Table I, the majorportion of--the products secured from g p the reaction is made up of thedesired unsaturated alco- Example .1 I hols and ethers. A nitrogenpurged mixture consisting of 1.0147 grams Example 3 oftetrakis(triphenylphosphine)palladum, 17.4 grams of Followin theprocedure of Example 1, a number of butadiene, 50 milliliters oftetrahydfofuran a 10 m l tests were conducted wherein butadiene wasreacted with liters of water were introduced into the reaction vessel ofwater in the presence of a tertiary butanol diluent, The

a typical Parr pressure apparatus. After addition of the catalystemployed was tetrakis(triphenylphosphine) palcatalyst, process reagentsand solvents, the reaction vessel ladium. Benzyltrimethyl ammoniumhydroxide wa used was shaken and simultaneously heated to 60 C. The reascocatalyst in Run No. 2. The results of the tests and action wascontinued at 60 C. for 16.5 hours. Upon comthe conditions at which theexperiments were carried out pletion of the reaction period, thereaction vessel was are set forth in Table II below.

TABLE II wt t Yield ofB H20. .(CHQZOHOH.v 52mm e. P od t. -l G-I g. m1.ml. C. hrs. g. A B C 'D" catalyst Pd e Initial charge-not all consumed.b 0.5 ml. of benzyl trimethyl onlum hydroxide added.

vented and the liquid contents diluted with three volumes The above dataclearly indicate the utility of the reaction of water. Thereafter, theorganic layer was separated for the formation of unsaturated alcoholsand ethers. As from the water layer and the latter extracted with pen-'60 is evidenced from the data, the use of a tertiary alcohol, came. Theresulting pentane layerwas then washed with namely tertiary-butanol, asthe' reaction solvent clearly water and then dried overmagnesiumsulfate. The pen- A resulted in the formation of muchless ether product.tane was then evaporated from thereaction product? Using" thetertiary-butanol solvent system, the selectivity The resulting product(3.0 grams) was subjected to gas of the process was greatly directed tothe formation of the chromatographic, infrared and nuclear magneticresounsaturated alcohol. Runs 1 and 2 demonstrate the denance spectralanalysis and was found to contain 65.9 sirable effects secured with theuse of a quaternary amwt. percentof 1,3,7-octatriene, 7.9 wt. percent ofl-octamonium base cocatalyst. In-Run 2 wherein a benzyltri- 2,7-dieno1and 15.5 wt. percent of bis(2,7'-octadienyl) methylamrnonium hydroxidecocatalyst was used, the rate ether. The unsaturate'd alcohol was formedat a rate of of formation of alcohol per gram of palladium per hour0.233 grams of alcohol per'gram of catalyst per hour was approximatelytwice that secured with an identical and a yield of 2.52 grams ofproduct per gram of pallarun wherein no quaternary ammonium hydroxidewas dium was secured.

used. H I r v v Example 2 v l i Example 4 Following the generalprocedureof Example 1, a series Following the general procedure ofExample 1,a numof experiments were conducted wherein buta diene was berof tests were conducted wherein-butadienewas .re-

8 acted with the various types 'of aliphatic rnonoalcohols at rated'fron r'the' reaction product. The product was sub 80 C. In each'of thetests, the catalyst employed was jected to gaschroinatogr'aphy and theresults summarized tetrakis(triphenylphosphine)palladium" alone 'orin"'c91 11- in Table i 1 i Product 3-methoxy 1,7-1-methozy-2.7-octadiene octadiene [(CeH5CH9)aP]4Pd, Butadiene, Temp.,Time, Wt. GJg. Wt. GJg. Exp g. g. 0. hrs Grams percent Pd/hr. percentPd/hr. 0. 1119 11. 100 0. 35 1 10. 85 92. 4 3, 180 7. 6 260 0. 0841 11.0 100 0. 42 12. 50 90. 1 4, 000 7. 6 340 0. 1221 12. 0 100 0. 28 .13. 2092. 6 4, 450 7. 3 350 0. 1010 11. 0 120 0. 27 12. 25 89. 3 4, 990 10. 1560 0. 1149 11. 0 120 0. 18 12. 60 91. 4 6, 920 8. 7 660 0. 1195 12. 0120 0. 20 12. 60 91. 6 6, 010 8. 4 550 0. 1057 11. 0 140 0. 15 11. 9589. 6 8, 400 10. 2 960 0. 1123 11. 5 140 0. 11. 95 91. 5 8, 070 8. 6 7600. 1046 12. 0 140 0. 16 12. 65 91. 5 8, 600 8. 3 780 bination withbenzyltrimethylammonium methoxide. The The above tests clearly point.out both the substantial results of the test and conditions at whichthe experiments activity of tetrakis (tribenzylphosphine) palladium as awere carried out are set forth in Table III below. catalyst, and thedesirability of using as high a reaction TABLE III Grams product/gramPd/hr.

Grams Alcohol Milliliters Grams Time, Grams l-octadienyl 3-octadienylRun catalyst type alcohol butadiene hours product ether ether. I

0. 0974 Methanol 100 8. 7 1. 87 8. 20 460 22. 6 0. 0975 B 100 8. 5 1. 879. 00 466 58. 0 0. 0484 100 10. 3 3. 00 3. 212 8. 58 0. 0479 b 100 9. 23. 00 4. 80 293 27 7 0. 0419 100 10. 0 3. 00 0. 0O 0. 0480 h 100 10. 53. O0 8. 10 447 23. 2 Y 0. 0483 100 10. 6 3. 00 2. 10 12A 5 51 0. 0487 R100 10. 0 3. 00 6. 00 372 16. 0 0. 0465 100 10. 1 3. 00 0. O0 0. 0448100 10. 5 3. 00 1. 00 447 23 2 0, 0481 80 7. 3 17. 3 0. 00 0. 0497 b 808. 0 19. 0 2. 79

l 3 milliliters of a 40 wt. percent solution of benzyltrimethylammoniummethoxide also added. b 1 milliliter 010.186 N benzyltrimethylammoniummethoxide in methanol also added.

The above tests clearly point out the desirability of temperature as isconsistent "with catalyst stability, e.g.

using a basic cocatalyst in conjunction with the general 140 C.

zero valent palladium/activator catalyst system. In each 40 Ex m l 6 ofthe tests wherein the base material was present, higher yields ofproduct were secured as compared with sub- Following the generalprocedure of Example 5, a series stantially identical tests wherein nobase was used. As of reactions were runin which the catalyst wastetrakis shown in Runs 9-12, the presence of the basic cocatalyst(diphenylalkylphosphine)palladium; L Pd where L=diserved to promote" theformation of the product within phenylalkylphosphine. The results arelisted in Table V.

TABLE v Product 7 3-meth0xy-1,7- LlPd catalyst 1-methoxy-2,7-octadieneoctadicne Butadiene, Temp., Time, Wt. G./g. Wt. G./g. Exp. L equalsGrams g. 0. hrs. Grams percent Pd/hr. percent Pd/hr 1 ((nHmPcH, 7 0.182712.3 140 0. 25 11.54 81.5 1,700 12.5 270 (COH5)2PC2H5 0.1475 12.0 1400.20 14. 48 82.0' 3,500 11.1 470 3 (COH5)2PI1C5H13 0.0879 10.5 140 0.2510.31 52.1 4,280 8.3 430 5 (Chimp-110121121 0.0819 10.1 140 0.25 9.00 889 5,580 5 9 560 (CaH5)2P-nOmHa: 0.0703 10.8 140 0.30 10.55 83 2 7,230 81 000 (C6H5)2PDC20H41 0.0959 10.3 140- 0.33 10.50 88 8 5,420 9 3 570 s(CoH5)2P-SC4H9 0.1175 13.5 120 0.15 13.85 92 5 7, 350 6 8 540 relativelybrief reaction times even when branched chain The above tests clearlyshow the substantial activity alkanols were used. a oftetrakis(diphenylalkylphosphine)pa1ladiu1n compounds Example 5 ascatalysts, and the increase in catalytic activity as the straight chainalkyl group increases in length from 1 to 16 carbon atoms. A substantialincrease in catalytic activity is also obtained when the alkyl group iseither cyclic, experiment 4, or branched, experiment 8.

A nitrogen purged mixture of tetrakis(tribenzylphosphine)-pal1adium,butadiene and 100 ml. of methanol were placed into a pressure bottle,stirred magnetically and heated in an oil bath. Upon completion of thereaction period, the-reaction vessel was vented and the liquid con-Example 7 tents diluted with three volumes of water. Thereafter theorganic layer was separated from the water layer and the Following thegeneral procedure of Example 5, a series latter extracted with pentane.The combined organic and of reactions were run in which the catalyst wastetrakispentane layers were then washed with water and dried(phenyldialkylphosphine)palladium, L Pd where L: over magnesium sulfate.The pentane was then evapophenyldialkylphosphine. The results are listedin Table VI.

TABLE VI Product 3-methoxy-l,7- 1-methoxy-2,7-oetadiene octadiene LrPdcatalyst Butadiene, Temp., Time, Wt. GJg. Wt. G./g. Exp. L equals Gramsg. 0. hrs. Grams percent Pd/hr. percent Pd/hr.

1 CnHP(C2H5)2 0.0863 9.5 140 0.50 10.41 72. 7 1,190 13.4 220 2C6H5P(11-C6H13 2 0. 1441 12. 6 140 0.33 8.00 87.9 1,640 7. 9 150 Theabove tests clearly show the activity oftetra(phenyldialkylphosphine)palladium compounds as catalysts.

Example 8 Following the general procedure of Example 6, a series ofreactions were run in which the catalyst was tetrakis-(trialkylphosphine)palladium, L Pd where L=trialky1 phosphine. Theresults are listed in Table VII.

prised of tetrakis(phenyldialkyl phosphine) palladium wherein the alkylis selected from the group consisting of ethyl and n-hexyl groups and abasic catalyst selected from the group consisting of tetraalkyl andtrialkylaralkyl ammonium hydroxides and alkoxides having from 4 tocarbon atoms at a temperature ranging from 0 to 160 C., and thereafterrecovering a yield of said unsaturated ethers.

TABLE VII Product 3-methoxy-1,7- 1-methoxy-2,7-octadiene oetadiene LrPdcatalyst Butadiene, Temp, Time, Wt. GJg. Wt. G./g. Exp. L equals Gramsg. C. hrs. Grams percent Pd/hr. percent Pd/hr.

1 P(n-C4Ho)a 0. 1493 12. 8 140 0. 12. 96 75. 9 2. 260 14. 0 420 2P(I1-CBH17)3 0. 1168 10. 5 140 0. 65 5. 88. 9 940 9. 5 100 The abovetests clearly show the activity of tetrakis-(trialkylphosphine)palladium compounds as catalysts.

What is claimed is:

1. A process for the formation of unsaturated ethers which comprisescontacting a C -C acyclic aliphatic conjugated diolefin and an alkanolhaving from 1 to 8 carbon atoms in a liquid phase, said liquid phasebeing free of dissolved oxygen, in the presence of a catalyst systemcomprised of tetrakis(tribenzylphosphine) palladium and a basiccocatalyst selected from the group consisting of tetraalkyl andtrialkylaralkyl ammonium hydroxides and alkoxides having from 4 to 20carbon atoms at a temperature ranging from 0 to 160 C., and thereafterrecovering a yield of said unsaturated ethers.

2. The process of claim 1 wherein said conjugated diolefin is butadiene.

3. A process for the formation of unsaturated ethers which comprisescontacting a C -C acyclic aliphatic conjugated diolefin and an alkanolhaving from 1 to 8 carbon atoms in a liquid phase, said liquid phasebeing free of dissolved oxygen in the presence of a catalyst systemcomprised of tetrakis (diphenylalkylphosphine) palladium wherein thealkyl group is one selected from the group consisting of methyl, ethyl,n-hexyl, n-dodecyl, n-hexadecyl, n-eicosyl and sec-butyl groups and abasic cocatalyst selected from the group consisting of tetraalkyl andtrialkylaralkyl ammonium hydroxides and alkoxides having from 4 to 20carbon atoms at a temperature ranging from 0 to 160 C., and thereafterrecovering a yield of said unsaturated ethers.

4. The process of claim 3 wherein said conjugated diolefin is butadiene.

5. A process for the formation of unsaturated ethers which comprisescontacting a C -C acyclic aliphatic conjugated diolefin and an alkanolhaving from 1 to 8 carbon atoms in a liquid phase, said liquid phasebeing free of dissolved oxygen in the presence of a catalyst system com-6. The process of claim 5 wherein said conjugated diolefin is butadiene.

7. A process for the formation of unsaturated ethers which comprisescontacting a C -C acyclic aliphatic conjugated diolefin and an alkanolhaving from 1 to 8 carbon atoms in a liquid phase, said liquid phasebeing free of dissolved oxygen, in the presence of a catalyst systemcomprised of tetrakis (trialkyl phosphine) palladium wherein said alkylis selected from the group consisting of n-butyl and n-octyl groups anda basic cocatalyst selected from the group consisting of tetraalkyl andtrialkylaralkyl ammonium hydroxides and alkoxides having from 4 to 20carbon atoms at a temperature ranging from 0 to C., and thereafterrecovering a yield of said unsaturated ethers.

8. The process of claim 7 wherein said conjugated diolefin is butadiene.

References Cited UNITED STATES PATENTS 3,530,187 9/1970 Shryne 260-614AA X 3,499,042 3/1970 Smutny 260-6l4 AA 3,407,224 10/ 1968 Smutny260-614 AA X 3,267,169 8/1966 Smutny 260-612 D X 3,489,813 1/1970Dewhirst 260-614 AA X 3,574,717 4/1971 Lloyd 260--6l4 AA X OTHERREFERENCES Takahashi et al.: Tetrahedron Letters No. 26, pp. 2451- 2453,1967.

Takahashi et al.: Bull. Chem. Soc., Japan, vol. 41, N0. 1, pp. 254-255,1968.

HOWARD F. MARS, Primary Examiner U.S. Cl. X.R.

252-431 N, 431 P; 260-641, 683.15 D, 683.15 E

